Monday, September 6, 2010

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 060538
SWODY1
SPC AC 060537

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1237 AM CDT MON SEP 06 2010

VALID 061200Z - 071200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF SRN MN/WRN
WI/IA...

...SYNOPSIS...
MID-LEVEL TROUGH/LOW -- INITIALLY OVER MT/WY/CO -- IS FORECAST TO
SHIFT QUICKLY ENEWD WITH TIME ACROSS THE CENTRAL AND NRN PLAINS
THROUGH THE AFTERNOON...AND THEN INTO/ACROSS THE UPPER MS VALLEY
THROUGH THE LATTER HALF OF THE PERIOD.

AS THIS OCCURS...SUBSTANTIAL CYCLOGENESIS IS FORECAST ACROSS THE
CENTRAL/N CENTRAL CONUS...WITH THE LOW SHIFTING FROM NEB INTO SRN MN
THROUGH THE DAY...AND THEN INTO THE WRN UPPER GREAT LAKES REGION BY
07/12. THIS LOW -- AND THE ASSOCIATED SWWD-TRAILING COLD FRONT --
SHOULD FOCUS A LINE OF VIGOROUS/SEVERE STORMS FROM LATE AFTERNOON
INTO THE EVENING HOURS.

ELSEWHERE...T.D. 10 IS FORECAST TO SHIFT NNWWD ACROSS THE WRN GULF
OF MEXICO TOWARD S TX -- POSSIBLY STRENGTHENING TO TROPICAL STORM
LEVELS DURING THE PERIOD.

...SRN MN AND PARTS OF WI SWWD INTO THE MID MO VALLEY REGION...
CAPPING LAYER OF WARM AIR IN THE 850 TO 700 MB LEVEL IS FORECAST
ACROSS THE SLIGHT RISK AREA INTO THE AFTERNOON...AS A DEEPENING
CYCLONE SHIFTS NEWD ACROSS THE MID MO VALLEY AND INTO SRN MN.
COOLING ALOFT WILL CONTRIBUTE TO SOME CAPE DEVELOPMENT ABOVE THE
WARM LAYER...WHILE FLOW FIELD THROUGH THE LOWER HALF OF THE
TROPOSPHERE STRENGTHENS.

AFOREMENTIONED CAPPING SHOULD SUPPRESS DEEP CONVECTION FOR MUCH OF
THE AFTERNOON. HOWEVER...STRONG UVV ASSOCIATED WITH THE
ROBUST/COMPACT UPPER SYSTEM -- FOCUSED AT THE SURFACE NEAR THE LOW
AND ALONG THE TRAILING COLD FRONT -- SHOULD EVENTUALLY ALLOW STORMS
TO DEVELOP IN THE ERN SD/SRN MN/IA VICINITY...AND THEN SWWD ACROSS
NWRN MO/KS. WHILE WIND PROFILES ACROSS THE SLIGHT RISK AREA --
FEATURING SUBSTANTIAL VEERING/STRENGTHENING WITH HEIGHT -- WILL BE
SUPPORTIVE OF SUPERCELLS...LINEAR FORCING AND DEGREE OF WARM SECTOR
CAPPING SUGGEST THAT CONVECTION SHOULD REMAIN CONFINED TO THE
IMMEDIATE FRONTAL ZONE...GROWING UPSCALE INTO A MORE LINEAR
CONFIGURATION RATHER QUICKLY AFTER INITIAL STORM DEVELOPMENT. THUS
-- WHILE SOME TORNADO THREAT APPEARS TO EXIST ACROSS IA AND NWD/NWWD
TO THE N OF THE LOW/WARM FRONT WHERE ELY/SELY LOW-LEVEL FLOW WILL
EXIST...MAIN THREATS WILL LIKELY BE HAIL AND/OR LOCALLY DAMAGING
WINDS. FARTHER SWWD ALONG THE FRONT...STORMS WHICH DEVELOP ACROSS
KS AND VICINITY WILL LIKELY REMAIN LESS VIGOROUS GIVEN WEAKER SHEAR
PROFILES. STILL...ISOLATED STRONGER CELLS COULD PRODUCING BRIEF
GUSTY WINDS AND/OR MARGINAL HAIL.

STORMS SHOULD CONTINUE INTO THE EVENING ALONG THE ADVANCING
FRONT...BUT WITH THE LOSS OF HEATING AND GRADUAL REDEVELOPMENT OF
CAPPING...A DECREASING TREND IN STORM ACTIVITY AND ASSOCIATED SEVERE
POTENTIAL IS EXPECTED.

...COASTAL SRN/SERN TX...
TROPICAL DEPRESSION #10 HAS FORMED IN THE SWRN GULF OF MEXICO...AND
IS FORECAST TO APPROACH S TX LATER IN THE DAY 1 PERIOD. AS THIS
OCCURS...INCREASING LOW-LEVEL FLOW FIELD COULD EVENTUALLY SUPPORT
WEAK UPDRAFT ROTATION WITH STRONGER CELLS WITHIN THE CONVECTIVE
BANDS SURROUNDING THIS SYSTEM. THEREFORE...WILL MAINTAIN LOW
TORNADO PROBABILITY ACROSS THIS AREA.

..GOSS/STOPPKOTTE.. 09/06/2010

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@LISTSERV.ILLINOIS.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.

No comments: